Introduction to Food Science and Technology 101

Roshina Rabail
M.Phil Human Nutrition and Dietetics
M.Sc. Food and Nutrition
Former Dietitian CMH Okara Cantt. & Shifa Int.
Hospital Islamabad.
9/02/2019 Roshina Rabail (FST-101) 1


 Food science is the application of the basic sciences and
engineering to study the fundamental physical, chemical,
biochemical nature of foods and the principals of
processing.
 Food is any substance that, when ingested, usually will
supply nutrients that nourish the body.
 Nutrients are the constituents of food i.e. Carbohydrates,
Proteins, Lipids, Vitamins, Minerals and Water.
 Processing involves any operation that will alter the value
of food in order to enhance: shelf life, consumer acceptance
and nutrient load.
Food Science


 A Food Scientist studies the physical, microbiological, and
chemical makeup of food. Depending on their area of
specialization, Food Scientists may develop ways to
process, preserve, package, or store food, according to
industry and government specifications and regulations
 This study involves knowledge about:
 The nature of food and its composition.
 Its behaviour to different conditions (processing,
preservation, storage).
 Causes of spoilage.
 Principles of processing and preservation methods.
 Improvement in food quality (attractive, safe, nutritious)
Food Science


 Food Science emerged as a discipline in early 1950’s.
 Broad discipline that holds many specializations:
 Food Engineering/Technology- engineering concepts
start from the selection of raw food to its processing &
preservation
 Food Microbiology- microbial ecology related to food,
food spoilage
 Food and Nutrition- basic composition, structure,
properties, effects of general health
Food Science


 The terms Food Science and Food Technology are
often used synonymously.
 Food Technology is the application of food science
to the selection, preservation, processing, packaging,
distribution and use of safe, nutritious, and
wholesome food.
 Food Science and Technology is the application of
physics, chemistry, microbiology, engineering and
nutrition to the handling, processing and storage of
food.
Food Technology


 Food Chemistry/Nutrition
 Food Engineering/Technology
 Food Microbiology
 Sensory Science
 Food Processing & Packaging
 Food Safety & Defence
 Product development
 Education & Careers
 Public Policy & regulation
 Sustainability
Core areas in Food Science


 Who can you work for???
 Food processors/Food Industry
 Research Institutes
 Academia/Teaching Institutes
 Self-employed/Consultant
 Government/Non-government organizations
 Food service organizations
 Testing laboratory
(For details consult chapter #1 Food Science and Technology by J.A. Awan)
Career Opportunities


Many disciplines from basic applied sciences
are involved primarily in two different ways
in the applications of Food Science.
 Scientific- involving physics, chemistry, biology
& microbiology.
 Technological- involving engineering,
processing, manufacturing, packaging,
distribution etc.
Relationship with other disciplines

 Major contributions of other disciplines in Food
Science:
 Physics-
 Selection of raw & processed food material,
 Food pH, humidity, moisture contents,
 Food handling, packaging, transportation equipment.
 Heating, cooling & evaporation of food material.
 Chemistry-
 Chemical & biochemical nature of food
 Chemical reactions of metabolism, spoilage & processing
 Food analysis procedures


 Engineering-
 Conversion of raw products into finished ones
 Developing, processing, packaging and storing
equipment and machinery
 Biology-
 Botany, plant pathology & genetics are involved in the
breeding of new varieties
 Entomology, parasitology & zoology are involved in
the growth of healthy plants and animals
 Human physiology involved in understanding how
food will gets metabolised inside the body


 Microbiology-
 limiting food spoilage issues
 introducing beneficial cultures to develop
products like yogurt, leavened bread, cheese,
pickles, sausages etc.
 processing techniques i.e. pasteurization,
sterilization, irradiation.
 Computer Science-
 involved in computing, calculating, recording and
reporting data


 In general food science and technology has:
 Enormous impact on the quality of human life
 Developed as world’s largest industry
 Processing unlimited variety of foods
 Transformation of agriculture from subsistence
farming to industrial farming
 Production of food for more than 100 families
 Food freshness retention
 Deterioration and spoilage prevention
 Supplying good quality food to the distant areas
Significance of Food Science and Technology


Regulating food supply:
 Regulating market prices in off season by proper
storage and preservation of the excess food.
 Food supply during off season to meet the
demand.
 Food supply to non-food producing areas.
 Food supply to far off places and ease in fruit and
vegetable export.


Consumer convenience in:
 Food cleaning and preparation
 Food storage
 Cooking time reduction
 Clean, safe, wholesome food over the counter
 Nutrient enriched food products
 Special food for special cases like diabetes, heart
disorders, allergies etc.


Scientific expeditions/journeys and travels:
 Processed, preserved & canned foods to be taken
along on journeys
 North pole or Mount Everest
 Special foods for Astronauts
 Food served in Airlines
 Ships carry food for months


 Waste utilization & reduction in environmental pollution:
 Utilization of food waste (husk, peels, pits, seeds, stems,
leaves) to
 Develop new food products
 Enrich nutrient content of existing food products
(supplementation)
 Produce organic manure or fertilizers
 Production of fermented products
 Production of Oils, fibres or pectins
 Production in herbal supplements or medicines


 Economic gains
 Food industry emerged as the biggest industry with:
 Enormous economic gains and profits
 Second major employer of labour in Pakistan
 Provision of high direct or indirect taxes to government
 Provision of foreign exchange through export business
 Supplying material to numerous allied industries producing
chemicals, detergents, packaging, medicines etc.
 Transportation of raw and processed food items facilitate
transportation department


 Rise in Hunger Around the Globe:
 Hunger/undernourishment: dietary energy intakes
below the minimum levels necessary to achieve and
maintain a healthy weight.
 This chronic food deprivation has increased to nearly 821
million in 2017, from around 804 million in 2016.
 last 3 years have seen continuous increase in hunger
 About 1.2 billion people don’t get enough food
 792 million people in developing countries
 34 million in developed countries
Global and national food and nutrition situation


 Prevalence of Undernourishment(PoU) :
 Africa~ highest PoU~21%of the population (more than 256
million people).
 South America~ PoU increased from 4.7% in 2014 to 5.0% in
2017.
 Asia~ PoU for 2017 is 11.4% (more than 515 million people). PoU
decreasing trend seems to be slowing down significantly.
 Pakistan~ PoU was 19.9% in 2015, according to the World Bank
collection of development indicators, compiled from officially
recognized sources.
 Hunger in Pakistan
 Pakistan ranks 77th out of 109 on the Global Food Security Index.
 Six out of 10 Pakistanis are food insecure.
 Food insecurity persists although food production is sufficient to feed all Pakistanis.
 Almost half of women and children under five years of age are malnourished9/02/2019 Roshina Rabail (FST-101) 19


 Nutrition Situation in Pakistan:
 Adults:
 Low energy and protein availability per capita
 51% pregnant women-Anaemia
 37%- Overall iron deficiency anaemia
 46%- Vitamin A deficiency
 69%- Vitamin D deficiency
 47.6%- Zinc Deficiency
 Children <5:
 62%- Anaemia
 43.8%- Iron deficiency anaemia
 54%- Vitamin A deficiency
 40%- Vitamin D deficiency
 39%- Zinc deficiency


 Nutrition Situation Around the Globe:
 Pre-School Children
 About 160 million- severely malnourished
 13 million- Xerophthalmia
 500000 become partially or totally blind each year
 Child wasting: low weight for height (a strong predictor of mortality
among children under five)
 In 2017, 7.5% (50.5 million) were reported to be affected by wasting
(low weight for height) consequently putting them at a higher risk of
mortality.`
 Child stunting: low height for age (impaired growth and development
that children experience from poor nutrition, repeated infection, and
inadequate psychosocial stimulation)
 The number of stunted children has shown a slight decline of 9% from
165.2 million in 2012 to 150.8 million in 2017, but still nearly one third
of children under five in the developing world are stunted.


 Micronutrient deficiencies:
 Lack of essential vitamins and minerals required in small
amounts by the body for proper growth and
development.
 1.5 billion people (28% world’s population)- anaemia
 This anaemia prevalence in women increased from 30.3 %
in 2012 to 32.8% in 2016.
 1 billion people – Iodine deficient
 217 million people – goitre
 There is still a long road ahead to achieve the 2025 and
2030 targets for stunting, wasting, overweight, exclusive
breastfeeding, anaemia in women and adult obesity


 Reasons behind Rise in Hunger:
 The no. of extreme climate-related disasters (extreme
heat, droughts, floods and storms) has doubled since
the early 1990s.
 Average 213/year occurred in 1990–2016.
 Such disasters harm agricultural productivity.
 Drought only was responsible for more than 80% of
the total damage and losses in agriculture, especially
for the livestock and crop production subsectors.


 Food is that which nourishes the body. Food may also be defined as
anything ingested to meet the needs for energy, building, regulation and
protection of the body.
 Nutrition includes everything that happens to food from the time it is
eaten until it is used for various functions in the body.
 Adequate, optimum and good nutrition are expressions used to indicate
that the supply of the essential nutrients is correct in amount and
proportion.
 Nutritional status is the state of our body as a result of the foods
consumed and their use by the
 body.
 Health as the ‘state of complete physical, mental and social well-being and
not merely the absence of disease or infirmity.
 Malnutrition means an undesirable kind of nutrition leading to ill-health.
It results from a lack, excess or imbalance of nutrients in the diet. It
includes undernutrition and overnutrition.
Food Terminology


 Primarily there are two main sources of food:
 Plants Sources and Animal Sources
 Fishes are sometimes treated separately as a third group:
 Marine source: All kind of fish.
 Plant Sources:
 Fruits, vegetables, roots, stems, leaves, flowers, seeds, nuts,
legumes, pulses, herbs, spices etc.
 Animal Sources:
 Worldwide numerous species are considered edible.
 For Muslims only split-hoofed ruminants and selected birds are
Halal/edible.
 Cows, buffalo, sheep, lamb, goat, deer, camel, hen, duck,
turkey, quail.
Food sources


 Chemically food is composed of following
constituents:
1. Carbohydrates
2. Proteins
3. Fats/Lipids
4. Vitamins
5. Minerals
6. Water
Food Constituents


 Types of food constituents:
 On the basis of their functionality
1. Energy giving: Carbohydrates, Proteins, Fats
2. Growth & Body building: Proteins, Some minerals
3. Maintenance: Vitamins, Minerals
 On the basis of requirement:
1. Macronutrients: Carbohydrates, Proteins, Fats, Water
2. Micronutrients: Vitamins, Minerals
Food Constituents


 Carbohydrates:
 General chemical formula Cn(H2O)n
 Organic compounds
 Hydrates of carbon (2:1 ratio of H and O)
 Most abundant class of organic compounds on earth
 Carbohydrate Sources
 Carbohydrates are ingested in a variety of forms:
starch from grains, glycogen from meat, and
disaccharide and monosaccharide sugars from fruits
and vegetables.
Carbohydrates


 Formation:
 Formed by the process
photosynthesis
 6CO2 + 6H2O C6H12O6 + 6O2
 Classification:
 Simple: monosaccharide,
disaccharides
 Complex: oligosaccharides,
polysaccharides
Carbohydrates

1. Simple:
 These can’t be hydrolysed
any further
 Composed of 3 to 9
carbon atoms
 Only some trioses,
pentoses and hexoses
occur in nature
 Monosaccharide: 1sugar
unit e.g. Glucose,
fructose, galactose
 Disaccharide: 2 sugar
units e.g. maltose,
sucrose, lactose
Carbohydrates


1. Complex:
 These can be hydrolysed into
smaller simpler sugar units
 Composed of 3 or more than 3
sugar units attached by
glycoside bonds
 Oligosaccharides: 3-7 sugar
units e.g. raffinose, starchyose
 Poly Saccharides: more than 7
sugar units e.g. amylose(70-
350), amylopectin(several
hundreds)
 Starch, cellulose, glycogen,
pectin, agar etc.
Carbohydrates


 Carbohydrate metabolism
 Various biochemical processes responsible for the formation,
breakdown and interconversion of carbohydrates in living
organisms.
 During digestion, complex carbohydrates are broken down into
monosaccharides, which can be absorbed by the body.
 The most important carbohydrate is glucose, a simple sugar
(monosaccharide) that is metabolized by nearly all known
organisms.
 Carbohydrate Utilization
 The monosaccharides that are absorbed in the small intestine are
fructose, galactose, and glucose; the liver converts the first two
into glucose.
 Excess glucose is stored as glycogen in the liver or is converted
into fat and stored in adipose tissue.
Carbohydrates


 Carbohydrate Requirements
 The need for carbohydrates varies with a person's
energy requirements; the minimum requirement is
unknown.
 An estimated intake of 125-175 grams of carbohydrate
is needed daily to avoid protein breakdown.
 Energy share 50-60% from daily diet must be supplied
from Carbohydrates
 Carbohydrates provide 16KJ or 3.75 Kcal/gram energy
when metabolised
Carbohydrates


 Introduction
 Complex nitrogenous compounds
 Very high molecular weights
 About 2000 proteins exist in nature
 Composed of amino acids linked by peptide linkage
 Constituents of every living cell
 Participate in every aspect of cell metabolism
 Energy source providing 4 kcal (17 kJ) per gram
 Body protein is approximately 19% of flesh weight;
45% of this protein is present in muscle
Proteins


 Classification
 Classified on the basis of heat:
 Coagulable
 Non-coagulable
 Classified on the basis of solubility:
 Globulins
 Albumins
 On the basis of functionality:
 Structural, homones, enzymes, antibiotics, transport, storage,
toxins
 On the basis of composition:
 Simple
 Conjugated: phosphoproteins, lipoproteins, glycoproteins,
nucleoprotein, flavoproteins, metalloproteins, chromoproteins
Proteins


 Amino Acids:
 Building blocks of proteins
 20 naturally occurring
 Low molecular weight compounds
 Found in different combinations in different proteins
 Characterized by presence of a terminal (-COOH) & (-NH2)
 Connected by peptide linkages; formed between the
carboxyl and amino group of two adjacent amino acids.
 In addition, disulfide bonds may form between the sulfur
moieties of two sulfur-containing amino acids in the
polypeptide chain.
 May be alkaline, acidic or amphoteric in nature
 May be aromatic or aliphatic
Proteins

 Amino acids classification
 Essential:
 Required in daily diet
 Synthesized in low
quantity or cannot be
synthesized in human
body
 Non-essential:
 Not required in daily
diet
 Can be synthesised in
body from other amino
acids
Proteins


 Formation:
 Peptide linkage: Amino
group of one amino acid
links with acid group of
second liberating a water
molecule
 2 dipeptide, 3 tripeptide,
….. Polypeptide
 Hundreds of such peptide
bonds are present in
protein
Proteins


 Application: Functional/Nutritional/Chemical
 Functional Roles:
 Emulsification:
 Solubility: drinks, beverages, soups
 Foaming: whipping creams, bread dough
 Gelling ability: gelatin production, bread dough, yogurt
 Binding water and fat: Mayonnaise
 Nutritional Roles
 Provide energy for growth and maintenance of body
 Children require more protein as compared to adults
 Deficiency disease- Kwashiorkor
Protein


 Other Chemical Roles:
 Takes part in growth, maintenance and repair in following
ways:
 enzymes catalysing metabolic reactions
 structural proteins maintaining the shape of the cell
 hormones regulating cell activities,
 antibodies providing a defence mechanism
 contractile proteins
 transport proteins
 toxins and components of intracellular structures.
Protein


 Proteins may form biologically significant compounds
through conjugation with other molecules:
 chromo-proteins
 Lipoproteins
 Nucleoproteins
 Glucoproteins
 metalloproteins.
 Plasma proteins are also important in maintaining fluid and
acid-base balance.
 Digestive processes depend upon acids, alkalis, enzymes
from the stomach, intestinal glands and pancreas.
Protein


 Sources
 Animal:
 Lean meat, poultry, fish, egg, milk, cheese, yogurt are
rich protein sources
 Vegetable:
 Beans, pulses, nuts, seeds are good vegetative sources
 Cereals contain some amounts
 Vegetables and fruits generally poor sources
Protein


 Lipids constitute a heterogeneous compounds related by
their physical properties
 Insoluble in water
 Soluble in non-polar organic solvents
 alcohol, ether, benzene, chloroform and acetone
 Important dietary constituents
 High energy value
 Deliver fat soluble vitamins
 Include fatty acids, triglycerides, phospholipids,
sphingolipids, sterols, waxes, glycolipids and
lipoproteins.
Lipids


 Fats are esters of saturated or unsaturated fatty acids with
glycerol; (Fatty acid+glycerol is called glyceride)
 Fats and oils are basically mixture of triglycerides.
 Fatty acids vary with respect to their size, number and
position of double bonds found in the molecule.
 Classification:
 Classified by the number of carbon atoms:
 short chain (C4-6)
 medium chain (C8-12)
 long chain (C12+)
 Classification by nutritional requirement
 Essential: Linoleic and -linolenic acid
 Non-essential: Palmitic, stearic, oleic acid.
Lipids


 Classified by the saturation
 Saturated:
 devoid of double bonds
 general formula CH3(CH2)n COOH, (n= 2 to 24)
 Stearic acid CH3(CH2)16COOH
 Unsaturated:
 presence of double bonds
 Monounsaturated fatty acids:
 oleic acid (CH3(CH2)7 CH=CH(CH2)7 COOH)
 Polyunsaturated fatty acids:
 Linolenic acid
 CH3CH2CH=CH. CH2CH=CH. CH2CH=CH(CH2)7COOH
Lipids


 Properties
 Saturated fats solids at room temperature
 Oils/unsaturated fats are liquid at room temperature
 Saturation of the unsaturated fatty acids by hydrogenation
convert liquid oil into a hard fat (example, solid white
vegetable shortening and margarine)
 Mixing in water is dependent on emulsifier
 Milk (fat in water emulsion)
 Butter (water in fat emulsion)
 Fat/oils reacts with alkalis to form soaps
 Most of the fats melt between 30-40°C
 Smoke above 200°C
Lipids


 Rancidity
 Oxidative rancidity
 Oxidative change results in changed odour due to liberating
aldehyde, ketones or alcohols
 Oxidation is enhanced by the presence of light, high
temperature, inorganic elements like iron & copper
 Antioxidants like tocopherols are added and fats/oils are
stored in airtight containers and cool dark places.
 Hydrolytic rancidity
 Lipase hydrolysis of fats/oils
 Acid–glycerol bond is broken down
 Enzymes are destroyed or denatured by heat application
Lipids


 Nutritional Significance
 Most concentrated source of energy
 Supply 9 kcal/g (37 kJ/g)
 Increase palatability to food
 Enhance flavour and aroma
 Source of fat-soluble vitamins and essential fatty acids
 Required for growth, reproduction, skin integrity,
maintenance of cell membranes.
 Stored in the form of adipose tissue to insulates and
protects internal organs, maintain body temperature, while
serving as a reserve source of energy.
Lipids


 Sources
 Animal:
 Animal fats, butter, ghee
 Vegetable:
 Vegetable oils, oils of seeds and nuts,
Lipids


 These are required in very small (micro) quantities in
our daily diet.
 These include group of two constituents:
 Vitamins
 Minerals
Micro Food Constituents


 A group of organic compounds essential in small
quantities for the normal metabolism of other nutrients
and maintenance of physiological well-being.
 Essential/vital for life
 Cannot be synthesized by the body
 Must be obtained from the diet
 Found in varying quantities in different foods
 No single food contains all of them in sufficient quantities
 Absence or relative deficiency of vitamins in the diet can
lead to a characteristic deficiency state and disease
Vitamins


 Classification:
 The vitamins are classified according to their solubility in water
and fat solvents.
 Water Soluble Vitamins:
 vitamin B1 (thiamin), vitamin B2 (riboflavin), vitamin B3(niacin),
biotin, vitamin B6 (pyridoxine), pantothenic acid, folate, vitamin
B12 (cobalamin) and vitamin C (ascorbic acid).
 The water soluble vitamins are not stored to any great extent
and therefore need to be included in the diet every day.
 Fat Soluble Vitamins:
 vitamin A(retinol), vitamin D (calciferol), vitamin E
(tocopherol), and vitamin K (Phylloquinone)
 Fat soluble vitamins are stored in appreciable amounts in body
tissues and, do not have to be supplied daily in the diet.
Vitamins



 Introduction:
 Mixture of compounds having Vitamin A activity
 Include retinol, retinal, retinyl ester or retinoic acid
 Retinol is a pale, viscous, fat soluble compound
 Fairly heat stable but easily destroyed by oxidation
 Sources:
 Animal origin:
 Abundantly present in cod liver oil, beef liver, butter, cheese
 Plant origin:
 Present in the form of precursors carotenoids which may be converted
into vitamin A; dark green leafy vegetables (chlorophyll masks the
yellow carotene color), deep yellow vegetables, tomatoes and deep
yellow fruit.
 Carotenoids closely related natural pigments include Beta-carotene,
alpha-carotene, lutein and lycopene.
 Only beta and alpha carotene are precursors of retinol.
Fat Soluble Vitamins
Vitamin A


 Functions:
 Plays an important role in normal vision
 Essential for the integrity and normal growth of epithelial
cells
 Required for proper growth and development of bones and
teeth
 Important for the maintenance of membrane integrity and
functions
 Anti-infective
 Deficiency diseases:
 hyperkeratinization, night blindness, Bitot’s spots,
xerophthalmia, keratomalacia, and blindness.
Vitamin A


 Introduction:
 Not strictly a vitamin, since it can be synthesized in the
skin.
 Becomes essential/vital only when body fails to synthesise
due to inadequate sunlight exposure.
 Its natural form is Cholecalciferol or Vit D3: a white
crystalline compound that resembles to cholesterol.
 Stable to heat and processing.
 Functions:
 Regulation of calcium absorption
 Utilization of Calcium and Phosphorus
 Homeostasis
Vitamin D


 Deficiency Disease:
 Strict vegetarians are especially at risk of deficiency
 Rickets in children
 Osteomalacia in adults (softening of bones).
 Sources:
 There are relatively few sources of vitamin D
 Mostly found in animal origin of high fatty nature
 Oily fish, eggs, liver and butter providing modest
amounts
Vitamin D

 Found in many foods
 Known as Tocopherols and Tocotrienols
 Seven different forms exist
 Most active is α-tocopherol
 Lost during processing
 Function:
 Lipid-soluble natural antioxidant that can be replaced by
synthetic antioxidants
 Regulate reproductive function
 Maintain healthy immune system
 Prevent degeneration of tissues
 Protect hormones from oxidation
Vitamin E


 Dietary deficiency of vitamin E in human beings is
unknown.
 Patients with severe fat malabsorption may suffer
some forms of chronic liver disease
 Sources:
 Vegetable oils are rich sources of vitamin E.
 Significant amounts are found in nuts, seeds, eggs,
milk, most green leafy vegetables and a variety of fish.
Vitamin E


 Introduction:
 Discovered as a result of investigations into the cause
of a bleeding disorder (hemorrhagic disease)
 Three compounds have the biological activity of
vitamin K;
 Phylloquinone K1: Yellow viscous oil, found in dietary
origin (green leafy vegetables)
 Menaquinones K2: compounds synthesized by intestinal
bacteria
 Menadione K3: synthetic compounds that can be
metabolized to phylloquinone
Vitamin K


 Sources:
 Green leafy vegetables like spinach cabbage,
cauliflower and sprouts.
 In addition, soybean, rapeseed, cottonseed, and olive
oils are relatively rich in vitamin K
 Functions:
 Anti-haemorrhagic and required for blood clotting
 Liver damage
 Blood fails to clot
Vitamin K


 Introduction:
 Thiamine- white solid
 widely distributed in foods
 readily lost by leaching into cooking water
 unstable to light
 Functions:
 Coenzyme in glucose metabolism
 Energy-yielding metabolism at cellular level
 Takes part in nerve conduction therefore promotes healthy
nervous system
 Promotes appetite and digestion
Water Soluble Vitamins
Vitamin B1


 Sources:
 Potatoes, whole-grain cereals, peas, dry beans, milk,
yeast, meat, and fish are the major sources in most
diets.
 Beri Beri:
 weakness, palpitation of heart along with degeneration
of nervous system and odema (wet beri beri)
Vitamin B1


 Introduction:
 Riboflavin-yellow crystalline water soluble
 Occurs freely and as coenzyme FAD
 Deficiency is a significant public health problem in many
areas of the world
 Fairly stable to heat but sensitive to light
 Sources:
 Milk and dairy products are important sources providing
25% or more of total riboflavin intake in most diets
 average riboflavin status in different countries reflects milk
consumption to a considerable extent.
 Other rich sources are eggs, meat, fish, cheese, lean meat,
liver and dark leafy vegetables.
Vitamin B2


 Functions:
 Takes part as coenzyme FAD in energy-yielding
metabolism
 Healthy eyes and smooth skin
 Glossitis: swollen tongue and lips
 magenta tongue
 Seborrheic dermatitis
Vitamin B2


 Introduction:
 Niacin is not strictly a vitamin, since it can be synthesized in
the body from the essential amino acid tryptophan.
 Two compounds, nicotinic acid and nicotinamide have the
biological activity of niacin.
 Was discovered as the curative and preventive factor for
pellagra.
 Relatively resistant to heat, acid and alkali
 Sources:
 Liver, meat, poultry, fish, leafy vegetables, beans, cereals
 Chemical analysis reveals niacin in cereals (largely in the
bran), but this is biologically unavailable.
Vitamin B3


 Functions:
 Takes part in cellular metabolism and energy yielding
reactions
 Nicotinamide nucleotide coenzymes, NAD and NADP
 Deficiency disease:
 Pellagra: photosensitive dermatitis, like severe sunburn,
typically with a butterfly like pattern of distribution over
the face, affecting all parts of the skin that are exposed to
sunlight.
 Advanced pellagra is also accompanied by dementia (more
correctly a depressive psychosis), and there may be
diarrhea. Untreated pellagra is fatal.
Vitamin B3


 Introduction:
 The Latin word folium means “leaf,” and the word folate
from Italian means “foliage.”
 Folic acid - oxidized form of the vitamin found in fortified
foods
 Folate- reduced form of the vitamin found naturally in
foods and in biological tissues.
 Discovered during the search to cure the disorder
megablastic anemia.
 Properties:
 Soluble in hot water
 Crystallizes in yellow-orange needles
 Less heat stable
Folic Acid


 Functions:
 Synthesis of nucleic acid
 Formation of red blood cells
 Involved in the metabolism of several amino acids,
including histidine, serine, glycine, and methionine.
 Megaloblastic Anaemia
 Sources:
 Liver, kidney, green leafy vegetables, okra, peanuts,
Folic Acid


 Introduction:
 The Greek word pantos means “everywhere”
 It is widely distributed in food sources of all plant and
animal origins.
 Known as Pantothenic acid
 Occurs in foods in free and bound forms.
 About 85% of in food occurs bound as a component of
coenzyme A.
 Properties:
 Yellow viscous oil, soluble in water
 More stable in pH ranges 4-7
 Less heat resistants and lost during thermic processing.
Vitamin B5


 Deficiency disease:
 A deficiency is quite unlikely.
 “Burning feet syndrome”: numbness of the toes and a
sensation of burning in the feet.
 Sources:
 Meats (particularly liver), egg yolk, legumes, whole-
grain cereals, potatoes, mushrooms, broccoli, and
avocados, among other foods, are good sources of the
vitamin.
Vitamin B5


 Introduction:
 Pyridoxine represents the alcohol form, pyridoxal the
aldehyde form, and pyridoxamine the amine form.
 Functions:
 Acts as coenzyme
 Signs of vitamin B6 deficiency include sleepiness,
fatigue, cheilosis, glossitis, and stomatitis in adults.
 Neurological problems and convulsions in infants.
 Microcytic anemia due to impaired heme synthesis.
Vitamin B6


 Sources:
 Pyridoxine-found almost exclusively in plant foods.
 Pyridoxal phosphate and pyridoxamine phosphate are
found primarily in animal products.
 Good sources are meats, whole-grain products,
vegetables, some fruits (e.g., bananas), and nuts.
Vitamin B6


 Introduction:
 Discovered on investigating the cause of “egg white injury”.
 Eating raw eggs was known to result in hair loss,
dermatitis, and various neuromuscular problems.
 Combines with avidin (raw egg white protein) which makes
its unavailable .
 Later it was called vitamin H (the H refers to haut in
German and means “skin”) as well as vitamin B7.
 Properties:
 Crystallizes in needles in water.
 Heat and light stable
 Favourable pH range 5-8
Vitamin B7


 Functions:
 Takes part as coenzyme in carboxylation and
transcarboxylation reactions
 Deficiency:
 Lethargy, depression, hallucinations, muscle pain,
paresthesia in extremities, anorexia, nausea, alopecia (hair
loss), and scaly, red dermatitis.
 Sources:
 liver, soybeans, and egg yolk, as well as cereals, legumes,
and nuts.
 Can also be produced by intestinal bacteria.
Vitamin B7

 Vitamin B12 also called cyanocobalamin.
 Properties:
 Red coloured water soluble vitamin
 Stable in pH range 4-6
 Fairly heat stable
 Functions:
 Acts as coenzyme
Vitamin B12


 Deficiency occurs mostly in strict vegeterians
 Deficiency of vitamin B12, like that of folate, results
in megaloblastic macrocytic anemia
 Sources:
 Found only in animal origin
 The best sources of the cobalamins are meat and
meat products, poultry, fish, shellfish (especially
clams and oysters), and eggs (especially the yolk).
 Milk and milk products such as cheese, cottage cheese, and
yogurt contain less of the vitamin
Vitamin B12

 White crystalline substance
 Destroyed by heat, oxidation, light
 Lost during peeling, trimming, cooking.
 Functions:
 Ascorbic acid is required in several reactions involved in
body processes, including collagen synthesis, carnitine
synthesis, tyrosine synthesis and catabolism, and
neurotransmitter synthesis.
 It takes part as a reducing agent and important
antioxidant in the body.
 Strengthen blood vessels, Aids iron absorption, Healing of
wounds9/02/2019 Roshina Rabail (FST-101) 78
Vitamin C


 Scurvy
 Sources:
 The best food sources of vitamin C include asparagus,
papaya, oranges, orange juice, cantaloupe, cauliflower,
broccoli, Brussels sprouts, green peppers, grapefruit,
grapefruit juice, kale, lemons, and strawberries. Of
these foods, citrus products are most commonly cited
as significant sources of the vitamin.
Vitamin C


 Introduction:
 Very important in normal nutrition and metabolism
 Constitute only about 4% of total body weight.
 Functions: Their functions are many and varied.
 Two general functions include building and regulating
 They provide the medium essential for normal cellular activity.
 They maintain electrolyte balance/osmotic properties of body fluids.
 Provide hardness to bones and teeth.
 Function as obligatory cofactors in metallo enzymes.
 Classified by their occurrence in the Body:
 Macrominerals: required in amounts >100 mg/day
 Microminerals: required less than macrominerals.
 The major minerals of the human body:
 calcium, phosphorus, magnesium, sodium, potassium, and chloride.
Minerals


 Nutritionists categorize food on the basis of their
consumption pattern or functions
 Chemists categorize them on the basis of chemical nature
 Food processor categorize food on possibilities to
increasing its shelf life which include perishability and
pH values
 Classification of food Based on Perishability.
 Some foods have longer shelf life than others.
 Perishability refers to the quickness with which
a food gets spoilt.
Classification of Food


 Foods can be classified into three groups depending on
how long they can be kept without any treatment
 Stable
 Semi-Perishable
 Perishable
 Stable Foods
 Remain acceptable for long period of time if stored properly
 Usually from 3 months to 3 years
 Can be stored on shelf/room temperature
 Moisture content less than 15%
 Includes: honey, sugar, dry Cereals, legumes, pulses,
processed foods ( powdered milk, cereals, pasta) etc.
Classification on the basis of
Perishability


 Semi Perishable Foods
 Remain fit for consumption for a fairly long period of
time when handled and stored carefully.
 Shelf life ranges from few weeks to few months
 Moisture content 60-90%
 Included: potatoes, onions, ginger, garlic, some
varieties of apples, commercial processed foods like
scacks, cheese, icecream
 Spoiled by autolysis and growth of microorganisms
 Good handling and proper storage increases shelf life.
Perishability


 Perishable Foods
 Very short Shelf life usually from few hours to few days
 Needs immediate attention like refrigeration to prolong
shelf life.
 Moisture content 80-95%
 Readily spoiled by autolysis and microorganisms
 Include fresh commodities like fresh fruits, vegetables,
milk, meat, fish, eggs, processed foods like pasteurized
milk, cottage cheese, fresh cream, cakes, bakery biscuits,
bread etc.
 Canned foods are served as perishable when opened.
Perishability


 In chemistry, pH is a numeric scale
used to specify the acidity or basicity of
an aqueous solution.
 The acidity of foods has been used for
centuries to preserve foods.
 pH determine the rate of microbial
survivors.
 It gives information on:
 Food spoilage organism
 Food poisoning microorganism
 Choice of heat processing temperatures
Classification on the basis of pH


 Divided into four categories:
1. High Acid
2. Acid
3. Medium acid
4. Low Acid
 High Acid Foods:
 pH below 3.7
 Includes citrus fruits, fermented vegetables/pickles
 Spoilage organisms associated with these are yeast or moulds
 Boiling water can destroy these organisms
 Aciduric (acid resistant) bacteria can pose problems
 Food poisoning bacteria do not thrive in high acidic foods


 Acid Foods:
 pH 4.5-3.7
 Includes guava, orange, mango, pineapples, tomatoes etc.
 Spoilage is caused by enzymes and aciduric bacterias that
are low heat resistant and can be killed by pasteurization
 Examples are:
 some mesophilic spore forming bacteria like: Clostridium
Pasteurianium
 Bacillus thermoacidurans a spore forming bacteria cause
sour spoilage even in canned juices
 Food poisoning organisms usually don’t grow in acid foods


 Medium Acid Foods:
 pH 5-4.5
 Includes most meats and vegetable mixtures
 Same spoilage organisms as before
 Low Acid Foods:
 pH 5 or above
 Most vegetables (Okra, green leafy veg., carrots, beans), meat,
milk, eggs, fish
 Spoiled by enzymes and mesophilic spore forming bacteria,
thermophilic bacteria and non-forming organisms.
 Examples are: Clostridium Botulinum, Clostridium sporogenes.
 Destroyed at high temperature
 Food poisoning organisms prefer grow in medium and low acid
foods.


 Food Spoilage:
 Food spoilage is the process leading to a product
becoming either undesirable or unacceptable for
human consumption (with associated changes
involving alterations in taste, smell, appearance or
texture).
 Food spoilage may be caused by a variety of
mechanisms, including microbial, chemical and
physical reactions,
 Deterioration:
 Detrimental changes in the quality of food.
Mode of Food Spoilage


 Microbial spoilage is often due to the growth and/or
metabolism of spoilage bacteria, yeasts or moulds.
 Chemical spoilage may be via nonmicrobial enzymic
action, oxidation or non-enzymic browning.
 Physical spoilage include water loss; increase in moisture
of dry foods; freezer burn; and recrystallisation of frozen
foods.
 Mechanical agents: Insects, pests, rodents, birds.
 Autolysis spoilage is caused by auto-change mechanism
in living organisms that can deteriorate food constituents
i.e. over ripening & browing due to oxidation, softening
of fruit pectin by hydrolysis, wilting of leaves,
putrefaction of animal products.
Mode of Food Spoilage


 Must be kept in bags/silos because can get
damaged/spoiled if not stored properly
 Mechanical agents: Insects, pests, rodents, birds can cause
damage and leave their excreta/sheddings which make
food unfit for health
 Physical agents: Loss or gain of moisture during storage
due to temperature change and humidity level in
atmosphere can effect the quality of grains.
 Microorganisms: Gain in moisture can facilitate bacteria,
yeast and moulds multiplication producing mycotoxins.
 Autolysis: Further gain in moisture can facilitate the
germination of seed.
Mode of Spoilage of Stable Foods:


 Must be stored at cool, ventilated places.
 Mechanical agents: Insects, pests and rodents can bring
loss in quantity and quality, ultimately open ways for
microbial infestation.
 Physical agents: Loss in moisture can lead to shrinkage,
weight reduction.
 Autolysis: Enzymatic activities can lead to softening,
sprouting.
 Microorganisms: Attack on damaged/softened food
commodities include bacterial soft rot and black mould.
Mode of Spoilage of Semi-Perishable Foods:


 Mechanical agents: Insects, pests, rodents and birds can bring
loss in quantity and quality, ultimately open ways for microbial
infestation.
 Physical agents: Loss in moisture can lead to shrinkage, weight
reduction, high temperature can leads to wilting.
 Autolysis: Most fruits and vegetables got spoiled due to
ripening (a series of complex chemical and biochemical
reactions catalysed by enzymes) which results in softening or
wilting. Fruits and vegetables covered by an insoluble stiff
covering shield made of protopectin which can be
damaged/broken due to ripening/wilting of food.
 Microorganisms: Attack on damaged/softened food
commodities. Meat undergoes putrefaction and give off odour,
milk got curdle.
Mode of Spoilage of Perishable Foods:


1. Chemically induced autolysis
 Self destruction of living cells
 Caused by chemical compounds in food or enzymes
 Auto-oxidation in fats and oils
 Oxidative rancidity initiated by short wavelength light
 Uptake of oxygen by unsaturated systems and changing lipid radicals to
peroxiradicals
 Reaction with hydrogen forming hydroperoxides
 Critically high cccumulation of hydroperoxides leads to their breakdown
into aldehydes, ketones and acids (orourous/off flavour compounds)
 Accelerated by certain metals (copper), light, high temperature
 Changes in meat colour
 Deteriorative oxidation in meat results in off colour
 Oxidation changes myoglobin (purple coloured muscle pigment) to
oxymyoglobin (bright red)
 Further oxidation of oxymyoglobin changes it to metmyoglobin (brown
colour)
Spoilage by Autolysis


 Non-enzymatic browning
 Can be due to food interaction with metals, water, cooking equipment, pH
change or cooking temperature etc.
a) Millard Reaction
 A chemical reaction between an amino acid from protein with a carbonyl
group from reducing sugar.
 Brown nitrogenous polymers are formed
 Limits shelf life of various fruits, vegetables and juices
 Mostly undesirable nut only desired in roasting nuts, meat, snacks and
some bakery items.
b) Caramelization
 The temperature-dependent oxidation of sugar which involves of removal
of water from a sugar (such as sucrose or glucose) followed by
isomerization and polymerisation steps
 Used extensively in cooking for the resulting nutty flavor and brown color.
c) Changes in ascorbic acid
 Stored fruit juices changes to unfavourable brown colour due to oxidation of
L-ascorbic acid to D-dehydro-ascorbic acid


2. Enzyme induced autolysis
a) Enzymatic rancidity
 Hydrolysis of fats resulting in liberation of free fatty acids
and glycerol
 Off flavour in fats and oils
b) Putrefaction in fish
 Fish gut microorganisms promote this fish tissue autolysis
resulting in typical spoiled fish odour due to ammonia like
substances
c) Enzymatic browning
 Desirable colour of raisins, prunes, coffee
 Polyphenols converted to quinones resulting brown
pigment


 Following are the Spoilage agents:
1. Enzymes
2. Microorganisms
a) Moulds
b) Yeast
c) Bacteria
3. Other Factors affecting microorganisms
a) Food
b) Water
c) Oxygen
d) Temperature
e) pH
4. Insects, Rodents, Pests and Birds
5. Physical Factors
Spoilage Agents


 Harmful Effect:
 Enzymes are responsible for spoilage/deterioration of food
due to enzymatic autolysis in fresh fruits and vegetables
and ultimately decrease their shelf life.
 Beneficial Effects:
 Enzymes are biocatalysts that
 Accelerate the rate of chemical reactions
 Don't undergo any change in themselves
 Enzymes are proteins in nature that
 Are synthesized in living cells
 Acts in vivo and in vitro
Enzymes


 Enzymes are used in food industry for
 Pectolytic enzymes in fruit juice industry for clarification &
pigment extraction of fruit juices uses
 Tenderization of meat
 Manufacturing various dairy products like cheese
 Bread industry use amylolytic enzymes
 To improve the quality and quantity during olive oil
extraction
 Production of maltose
 Saccharification of starches requires amylases
 Saccharification of cellulose requires cellulases
 Production of alcoholic beverages
Enzymes

 Enzymes are classified into 6 groups on the basis of the reaction they
catalyze:
1. Oxidoreductases
 Oxidation/reduction reactions, e.g. cytochrome oxidase
2. Transferases
 Transfer of a functional group, e.g. transaminase
3. Hydrolases
 Hydrolytic reactions (hydrolysis in the presence of water) , e.g. esterases
4. Lyases
 Addition or removal of a group by deletion or formation of a double
bond , e.g. fumerase
5. Isomerases
 Intramolecular rearrangement, e.g. phosphohexose isomerase
6. Ligases
 Formation of covalent bond using energy , e.g. pyruvate carboxylase
Enzyme Classification

1. Effect of pH
 Enzyme mediated reactions require specific narrow pH range
 Below this pH range enzymes are inactive
 Above this pH range enzymes are denatured
 Selection of natural pH would allow microbial attack
 Low pH is preferred for food preservation by limiting microbial attack and
inactivating enzymes, e.g. pickling
2. Effect of Temperature
 Influence rate of enzyme activity
 Most enzymes active below 50ºC
 High or low temperature slow down the activity
 Lower temperatures of refrigerator or freezing inactivates enzymes
 High temperature usually 70-80ºC denatures enzyme, e.g. Blanching
3. Effect of Concentration
 Rate of enzyme activity id directly proportional to their concentration
Enzyme Efficiency


 Microorganisms are ubiquitous
 Found everywhere in soil, water, air, plants, animals,
humans
 Only not present in tissues of healthy plants and
animals
 Chief agents responsible for spoilage of food
 Categorized into Moulds, Yeasts, Bacteria
Microorganisms


 A mould is a fungus that grows in the form of
multicellular filaments called hyphae.
 These can be septate (can divide) or aseptate (cant divide).
 Forms a network called mycelium and produce spores.
 Spores released can spread to germinate on new surfaces.
 Used in production of various food products, organic
acids, antibiotics, vitamins and enzymes
 Grow rapidly in warm and damp climates, tropical
regions with moderate to heavy rains
 Aerobic in nature, therefore only grow over the surfaces
of foods like grains, tubers, bread, jam, fruits etc.
Moulds


 Examples are:
 Aspergillus
 Can grow at
fairly on foods with low water contents
 Mucor
 Moderate temperature and high humidity
 Penicillium
 Low temperature
 Can be prevented by controlling temperature, moisture
contents, keeping food in airtight containers
 Can be killed at high temperature above 100ºC.
Moulds


 Yeasts are eukaryotic, single, round-celled fungi.
 Divide rapidly by budding or binary fission.
 Require low pH and moisture higher than moulds.
 The first yeast originated hundreds of millions of years ago.
 1,500 species are currently identified. They are estimated to
constitute 1% of all described fungal species.
 In contrast, fungi that can adopt a single-celled growth habit
are called yeasts.
 Used in manufacturing of bread, enzymes, vitamins, juices, jam,
jellies, non alcoholic beverages etc.
 Can be seen over the surfaces of fruits.
 Can be destroyed at high temperatures by boiling or
pasteurization.
Yeasts


 Microscopic
 Single-celled
 Prokaryotes
 lacks a membrane-bound nucleus or any other membrane-bound
organelle
 Advantages:
 Used in production of:
 Organic acids, enzymes, antibiotics, vitamins, amino acids
 Yogurt, fermented meat, milk, fruits, vegetables
 Bacteria living inside gut helps:
 Produce some vitamins from B-complex.
 Digest cellulose in ruminants
 Disadvantages:
 Food Spoilage, Food born diseases, Food poisoning, Infections etc.,
Bacteria


 Classification on the basis of shape:
 Round- cocci (singular: coccus)
 Cylindrical/capsule-bacilli (singular: bacillus)
 Long coiled-spirilla (singular: spirillum)
 Short curved-vibrio
 Classification on the basis of temperature needs:
 Thermophilic: hot temperature loving (45-55ºC)
 Mesophilic: Room temperature loving (20-30ºC)
 Psychrophilic: Cold temperature loving (4-10ºC)
 Classified on the basis of Oxygen requirement:
 Aerobic: Needs oxygen
 Anaerobic: Doesn’t need oxygen
Bacteria

 Diverse in nature i.e. present in air, soil, water, human/animal guts
 Possess cell wall that may be covered with a protective covering
capsule or slime layer.
 More difficult to kill as compared to moulds and yeast
 Require high temperature or high acid treatments to kill
 Methods adopted are Boiling, cooking, Pasteurization and
sterilization
 Examples of toxic bacteria are: clostridium botulinum, salmonella,
shigella
 Factors affecting the growth of microorganisms:
 Food
 Temperature
 Moisture
 pH
 Oxygen
Bacteria


 Insects:
 Have 6 legs and hard outer skin/cuticle
 Life cycle consists of various forms like eggs, larva, pupa,
adult
 Examples are: weevils, beetles, moths
 Rodents:
 Mouse, rat, squirrel, rabbit
 Cannot survive in cold stores
 Eat and destroy food with filth
 Can be a carrier of different diseases like plaque, salmonella
 Birds:
 Source of filth and contamination in fruits and crops
Insects, Rodents, Birds


 Losses during harvesting, processing, storage
 Rains and storms
 Hot or cold temperature
 Undesirable changes in light
Physical Factors


1. Chemical spoilage by autolysis may be prevented or
delayed by the destruction or inactivation of enzymes or
chemical molecules.
2. Microbial spoilage may be prevented or delayed by
prohibiting microbial entry, their physical removal,
hindering their growth and activity or even destroying
them by using specialized techniques.
3. Mechanical spoilage caused by insects, rodents and birds
can be controlled or prevented by proper packaging.
4. Physical spoilage caused by the handling during
processing and storage can be reduced or prevented by
development of optimal processing and storage
techniques.
Principles of food preservation


 Prevention or delay of autolysis
a) pH
 Low pH by using organic acids e.g., pickles
b) High/low temperature
 High temperature like 100ºC for few seconds to few minutes-
blanching
 Low temperature involves refrigeration or freezing
c) Moisture
 Moisture is required for biochemical reaction by enzymes
 Removal of moisture by sun drying, dehydration, concentration,
evaporation
d) Good manufacturing practices to lower chemical autolysis
 During manufacturing use of appropriate temperature, proper
packaging and storage
Prevention or delay of autolysis

 Prevention or delay of microbial activity
a) Keeping microorganisms out
 Skin, peel, husk, shells provide protection
 Wax coating, canning, glass packaging, can be done to keep this covering intact
b) Removal of microorganisms
 Washing, trimming, filtration techniques are used
c) Creating unfavourable condition
 Anaerobic condition by vacuuming in canning
 Removal of moisture or water binding using sugars or glycerines (humectants)
 Use of chemicals like benzoic acid, sodium benzoate, lactic acid
 Low pH by acids in pickling
 Use of unfavourable temperature
d) Destruction of microorganisms
 High temperature:
 boiling, blanching, steaming, roasting, cooking
 Pasteurization: 65-88ºC
 Sterilization,: much higher temperature , above 100ºC
 Chemicals, ultraviolet rays for irradiation of food
Prevention or delay of microbial activity


 Control of pest activities
a) Insects
 Fumigation
 Insect proof containers
 Long acting insecticides
 Insect repellents
 Insect predators
 Impact based instrument to kill eggs
 Rise in temperature or infrared devices
b) Rodents
 Systemic control of rodents include poison baits, rat-traps
 Difficult invasion storing technique
c) Birds
 Noise making dummies of animal or human shapes
 Screen prevention
Control of pest activities


 Reduction in physical defects
 Improper surface drying can be avoided using
ultraviolet lamps
 Improper crystallization
 Other defects include humidity control
Reduction in physical defects

Introduction to Food Science and Technology 101

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